Are you referring to the Put display to sleep when inactive for: under screen saver preferences/power management - On AC power tab ? It is set for 40 mins at the moment ...

Also, when I reboot the system I find myself in XFCE since I did not enable compiz at boot however, I am missing the minimize, restore and close window buttons on the top right of any window I open. When I enable compiz they come back along with Emerald.